1. Field of the Invention
The present disclosure relates to telecommunications in general, and, more particularly, to a technique for discovering proximate wireless devices.
2. Related Art
In general, the IEEE 802.11 standard (“802.11”) specifies an over-the-air interface between wireless devices, such as between a wireless client and an access point, or between a number of wireless clients. Within the context of 802.11, a Basic Service Set (BSS) is used to describe a collection of wireless devices which may communicate together within an 802.11 Wireless Local Area Network (“WLAN”). The BSS may, or may not, include an access point (e.g. to provide a connection onto a fixed distribution system such as an Ethernet network or to serve as an intermediary for communications between wireless devices). 802.11 provides methods (which may also be referred to as “mechanisms” or “protocols”) for wireless devices to discover a BSS with which they may join. However, 802.11 does not currently include a method for wireless devices to discover other proximate individual wireless devices.
Thus, said another way, current 802.11 standards provide methods for a device to discover a BSS, without specific identification of the devices which may be communicating within that BSS. 802.11 also does not provide for wireless devices to discover other wireless devices that may not be communicating within a BSS at all.
Two types of BSS networks exist: an Independent Basic Service Set (“IBSS”) and an Infrastructure Basic Service Set (“Infrastructure BSS”), and each of these types of networks provide methods for wireless devices to discover the respective BSS. A network set up as an IBSS may also be referred to as an “ad-hoc network,” and a network set up as an Infrastructure Basic Service Set may be referred to as an “infrastructure network.”
Wireless devices communicating on an 802.11 based infrastructure network can discover nearby BSSs through a method known as background scanning. Background scanning is further categorized as either active scanning or passive scanning. In particular, during active scanning, a wireless device may discover a BSS by periodically transmitting probe requests. An access point associated with a BSS is configured to respond to probe requests with a probe response to the scanning wireless device. The probe responses identify the BSS and may also include information the scanning wireless device may need to connect to the BSS.
In addition to the active scan, wireless devices may discover a BSS by passively listening for beacons periodically broadcast by access points associated with the BSS. These beacons provide information about the respective BSS.
Current 802.11 protocols also provide wireless devices with the ability to discover an existing IBSS Network (i.e. ad-hoc network) via an active scan. Although ad-hoc networks do not include an access point that can be used for responding to probe requests from scanning wireless devices, the protocol designates one wireless device in the ad-hoc network, at any particular time, as the device to receive and respond to probe requests, similar to the access point of the Infrastructure BSS. This designated device is typically the device that sent the last beacon, for example.
Additionally, an ad-hoc network may be discovered by a wireless device by passively listening for beacons carrying information about the IBSS. Specifically, a designated wireless device associated with a particular ad-hoc network is configured to transmit beacons that provide information about its associated IBSS.
Accordingly, existing discovery methods enable a wireless device to discover networks (e.g., BSSs), as opposed to discovering other individual wireless devices. The discovery of individual wireless devices may be advantageous for a number of reasons, such as enabling the ability to remotely connect to and/or configure a wireless device, as described in the co-pending, commonly-assigned, U.S. patent application Ser. No. 11/314,143, entitled “Systems and Methods for The Remote Connection and Remote Configuration of Wireless Devices,” filed concurrently with the present application and incorporated by reference herein.
The discovery of wireless devices is different from discovering a BSS for a number of reasons. For example, unlike a BSS (which always has a designated device for receiving probe requests), individual wireless devices are not always listening for transmissions from other wireless devices on the same channel (e.g. their base channel). Rather, wireless devices may periodically scan other channels or, for example, may turn off their receiver to save power. Accordingly, what is needed are systems and methods for wireless devices to discover other wireless devices, despite these complications.